1. Field of the Invention
This invention relates to a light measuring device switchable to a photo trigger mode in which light measurement is started in response to receiving a flash light from a flash device for measuring the flash light, and to a code trigger mode in which light measurement is started in response to a manual operation for measuring natural light.
2. Description of the Prior Art
Light measuring devices as described above that can be switched either to a photo trigger mode or a code trigger mode are known. For example, in U.S. Pat. No. 4,227,808 filed by the same assignee as that of this application, a light measuring device is disclosed with reference to its FIG. 3 as an embodiment. The light measuring device includes a manually operated mode selector for selecting either a photo trigger mode or a code trigger mode, and a switch manually operable for starting the light measurement when the code trigger mode was selected by the mode selector.
When the photo trigger mode is selected by the mode selector, the light measuring device mentioned above first starts the light measuring if upon receipt of a pulse light by a photodetector. Under this mode the light measurement will not be started even if the above mentioned switch is manually closed.
Conversely, if the code trigger mode is selected by the mode selector, the light measurement will be started by the closure of the switch. However, under this code trigger mode, the light measuring will not start even if a pulse light impinges upon the photodetector before the closure of the above switch. Consequently, the photo trigger mode is normally used for measuring the flash light while the code trigger mode is used for measuring the natural light.
However, this device requires two manually operating members, i.e., a mode selector and a manually operable switch, so that it is complicated in construction and not convenient for operating because it requires two operations, that is, switching of the mode selector and then closing of the manually operable switch when the light measurement is to be started after switching from the photo trigger mode to the code trigger mode.